SPECULATIONS:
How many patients remain alive, what is the break down and what are the implications?
As of a year ago, Dr. Bosch indicated that there were a little more than 100 patients alive. Upon information and belief, the more precise number is 109 patients that were alive as of the 2017 spring refresh. Dr. Bosch also stated that the eventing rate was about 2 per month. It most probably has slowed down below that rate. If we assume this eventing rate, the number of patients still alive would be 85.
Assuming that mesenchymal accounts for about 40% of the trial population, we can estimate the breakdowns among mesenchymal/non-mesenchymal among the Tx, Xover and non-Xover groupings. Mesenchymal alone has been estimated to constitute between 30% and 50% of all stage IV glios. The mesenchymal grouping alone at 40% is likely to be conservative.
Applying the 40%, there are 132 mesenchymal patients out of a total of 331. The non-mesenchymal number of patients is then 199. The spread among three groups, Tx, Xover and non-Xover is as follows:
Tx: 88 mesenchymal(M) and 133 non-mesenchymal(NM). NM is further broken down between pro-neural(P) and non-proneural(NP). P is estimated to account for about 13%. Thus the breakdown is 28P and 105NP. Total Tx is 221 patients. Of the 88M, 55% are estimated to be alive as of spring refresh 2018 or 48 patients. Of the 133 P and NP patients, roughly 15% are expected to be alive or about 20 patients. Total Tx alive are 68 patients which comprises 31% of the total Tx group and 20.5% of the total of 331 patients.
Xover: 44 M and 33 NM. It is estimated that approximately 25% of M are still alive or 11 patients. It is estimated that 10% of the NM are still alive or 3 patients. Total Xover patients alive are 14 and this constitutes about 18% of the total Xover group and about 4% of the total of 331 patients.
Non-Xover: out of a total of 33 patients that did not cross over, about 10% or 3 patients are still alive and are probably all pro-neural out of a total of 15 such patients in that group. It is assumed that none of the pro-neutrals in this group crossed over.
Therefore: total patients alive are Tx(68) + Xover(14) + non-Xover(3)= 85 patients. Of the treated group--early plus late--of 82, this constitutes about 25% of the total of 331 patients and about 28% of the early plus late treated grouping of 298 patients.
In my earlier post where my mathematical model used a blended mOS of 23 months, a Tx of 25 months was estimated. With the foregoing breakdown of mesenchymal patients, mesenchymal Tx is estimated to be approximately 32 months. If the blended mOS moves further to the right as a result of 2018 data refresh, the numbers could be even better..
All IMHO.
